Well, it was wet and muddy out, so no good disc golf, but it wasn't raining! I just finished solvent welding the rest of it together, it wasn't as fumey this timr for some reason. Maybe a favorable wind. It takes 24 hours to cure, but I won't be able to get silicon greases, which I need for the pump, until Monday. I'm really happy with it so far, it is actually noticeably smaller when you bottom out the pipes during welding. Don't worry, even after this weak and next weekend, you will continue to get some coverage, as there is still a backpack to be made! Not neccasary for testing though.

It shoots a stream, about 15 feet.
Tested it yesterday. Wanted to see how good I was at keeping a secret. Better than I thought.

The pump needs work. It just doesn't seal tight enough to get the gun up to decent pressures. Any suggestions? The pump tube is not a variable. It is staying where it is. I might try my MD3k's pump to see if that will work, and to get some range measured for you.

From what I can tell you've been using Ben's method for the pump construction? That is a tried and tested method and should be able to handle the pressure, but it can be tricky.

Pics would be helpful if available.

Until then I would suggest putting the end of the wooden dowel (I assume you are still using that) in water to expand the wood and help seal the o-ring (if you haven't already).

PVC electrical tape around the pump rod makes it travel straighter, and can improve the seal.

Also how many o-rings are you using at the minute? You could try 2-3 o-rings in separate 'valleys'/grooves. this should also straighten the pump rod, and prevent pressurised water seeping between the o-rings and the pump tube.

Are the o-rings loose in the grooves? If they are, a slightly thicker o-ring should sort that out or you could just cut new shallower grooves in the other end of the pump rod, and use that end instead with the current o-rings (even Ben had to do this when he cut his grooves too deep!). O-rings can be too thin to work well with wooden groove pumps. I would say that 1/16"(thickness) o-rings are too narrow, but 3/32" would be better. I personally don't like the idea of gluing o-rings into grooves, but have heard of pumps working with glued o-rings. WARNING! some glues can destroy some types of o-ring, and you can't replace the o-ring if it wears out or fails if it's glued in.

VASELINE!!! or any other petroleum jelly should be used, unless the o-rings are made of a rubber which will react with that (quick google search should find that out if you know what they're made of.) if you can't use vaseline, I've heard of some successes with some form of spray on teflon lubricant.

As far as I can tell, the pump SHOULD be hard to move, without any vaseline, as this makes a good seal. The vaseline will loosen the pump a bit. (Detailed in Ben's method)

Trying the max-D's pump is probably a good starting point, before making any irreversible changes to your homemade pump.

I can't be much more specific without some knowledge of where exactly the fault in the pump is. (pics of the current pump rod would help).

Never heard of the teflon tape method, but I suppose it can be undone if it doesn't work so it's worth a try (i'll have to look into that). Overall it sounds like a good place to start, and hopefully you get some better results from what otherwise sounds like a pretty good APH.